Magnetic material and method of producing it



35 ance with the invention is to preliminarily Patented June 14,

UNITED STATES PATENT. OFFICE.

LYALL ZICKBICK, E cnrcaeo rumors, ASSIGNOR T0 WESTERN ELEcrnIc COM- PANY, INCORPORATED, 0 NEW YORK, N. Y., A CORPORATION on NEW onx.

mAeNErIcia A'rEnIAI. AND METHOD or rnonucme rr.v

No Drawing.

Application filed March 25, 1925. Serial No. 18,324..

This invention relates to magnetic, matesomewhat difiicult to grind, but alloys conrials and methods of producing them, and

- has for its object thefproduction by a simplified and inexpensive method of a relatively cheap, brittle magnetic material having. improved desirable 1 magnetic. characteristics and which may be readily reduced to av finely divided form. V

The inventionis of particular advantage in the production of magnet cores, particularly loading coil cores of the so-called dust type, such as are describedin Patent No. 1,297,126, issued to Gustaf W. Elmen-on March 11, 1919, and other patents therein referred to; but it will be apparent from the following description that the material may be at to other uses aswill be indicated hereina er. I .The presentinvention is, broadly characterized by the incorporation with :a' mag-i netic material, of asmall percentage of an embrittling agent, such as antimony, for the purpose of hardening-and embrittling the magnetic material without impairing. the desirable magneticcharacteristics of the material.

Hardened magnetic material so obtained may be easily pulverized in a suitable mill after which it may be used in the manufacture of cores for loading coils and other apparatus. The invention can be applied to any of the magnetic materials, but

is of particular use with iron and nickeliron. V p

The referred method .of producing the finely ivided magnetic material in accordmelt it andthen incorporate a small amount of antimonywith the melted materiaL- The resultin alloy-is then poured, preferably a in .a sha low mold, and allowed to solidify. It is then foundto 'be in a porous, brittle condition after which it may be preliminarily broken u in a hammer mill andthen reduced to nely. divided form, preferably in thefitype of machine known as a ball mill. g

Where a good rade of commercial iron is employed, goo .results are obtained by employing-from about 1.75% to about 15% v of antimony. There may be other amounts of antimony which will give good results, but in the experiments onwhichthe present invention is based, the best results seem to be within the range given. Aniron-antimony alloycontain'ing 1.75% antimony is taining as much as 4% of antimony can be reduced to finely divided form in the manner. described in the preceding paragraph with very little difiiculty. In regard to the magnetic properties of the alloy, the magnetlc permeability seems to be somewhat greater and hysteresis losses somewhat less with smaller percentages of antimony. The magnetic characteristics of the material,

however, will be more fully referredto in a following paragraph.

Where magnetic 'alloys composed of iron and other materials are employed the best results will be obtained by employing a different percentage of antimony than when iron alone is used. As an example, where antimony to be added to a nickel-iron alloy for the purpose of embri'ttling it, a satisfactoryembrittling eifect is not obtained' with a percentage of antimony substantially less than 5%. At the same time. it is found that substantially more than 8% of antimony is apt to cause a considerable decrease in the high magnetic permeability (ill of the nickel-iron and for this reason where v the high magnetic permeability of nickeliron at low magnetizing forces is sought to be retained; it is notdesirable to employ more than 8% of the embrittling agent. For mechanical purposes the best amount of antimony seems to be about ti but where the electrical or magnetic character istics of the material are sought to ,be varied, a somewhat different percentage may be used and a satisfactory embrittling efl'ect obtained. I

When the finely divided magnetic mate rial has been obtained it may be employed in various manners where its magnetic properties can be utilized. This use may. entail the insulating of the particles from each other which may be accomplished by incorporatin the particles with some insulating material of either the organic or inor anic type which material may be either plastic or non-plastic, de ending upon the manner in whic the resu ting mixture is to be emplo 'ed. Where the dust is compounded wit a plastic insulator it may be treated in the manner described in the application of \Villiam Fondiller, Seria-I'No. 741,041, filed October 1, 1924. The use therein described is generally termed continuousloading and as described in such application it may be accomplished by compounding the maglow as 1.5 ohms per henri of inductance. b

netic particles with a plastic materialand extruding the resulting mixture onto a pon- I ductor or by incorporating the particles with an insulating enamel before the application thereof to the conductor, and then baking the enamel to cause the mixture to adhere to the conductor.

The iron-antimony particles are of par. ticular advantage in the production of magnet cores, particularly those for use in loading coils. These cores may be made in the manner described in the patent to Elmen mentioned above and the other patents therein referred to, the method being briefly to coat the particles with insulating material, preferably shellac, and then by great pressure tofor'ce the particles into the form of a core or into a plurality of solid portions which may be assembled to form a core.

The magnetic properties of the material embodying the features of the present .invention may be apparent from a consideration of the characteristics of a specific loading coil core formed thereof during the ex perimental work in connection with this invention. In this particular instance a good grade of commercial iron was melted in an induction furnace and then 6% of antimony was added thereto. The resulting alloy'was' poured into a flat mold and allowed to solidify after which it was broken up and reduced to finely divided form in the manner described hereinbefore. 'When the particles were sufliciently' fine to passthrough an SO-mesh screen they were tumbled with a quantity of feathered zinc in order to form a zinc coating thereon, the

details of this step" of the process being car ried on in the manner described in Patent -No."1,292,2l6, issued January 21, 1919, to

' J. C. Woodrufi. The zinc coated particles were then insulated with shellac and pressed into the form of a homogeneous solid with a pressure of 200,000 pounds per square inch, the details ofthese steps being substantially as described in Patent No. 1,274,952, issued August 6,- 1918 to J. B. Speed. The cpre produced in this manner was then tested and found to have a permeability of 44 at a flux density of 17 lines and a frequency of 900 cycles. Under the same conditions the hysteresis loss was 7.3 ohms per henri, while the power loss due to eddy currents was as It is understood, however, that this example is simply illustrative of one particular embodiment of the invention and that other materials, such as aluminum, silicon and tin, may be employed in other articles and may be produced byother processes and there fore the invention is to be limited only by the scope of the appended claims.

What is claimed is:

1. A method of producing magnetic material, whichconsists .in alloying antimony with a magnetic material, and reducing the resulting product to finely divided form.

2. As a new article of manufacture, an alloy of magnetic material and antimony reduced to finely divided form.

3. -A magnetic material comprising an alloy of iron and antimony reduced to finely divided form.

4. A method of producing magnetic material, which consists in alloying antimony with an iron-nickel alloy, and reducin the resulting product to-a finely divided orm. 5. A method of embrittling magnetic materials, which consists in alloying antimony 7. A method of embrittling iron-hickel 1- loys, which consists in alloying antimony therewith.

8.A magnetic material comprising'from 1.75 to 15% antimony and the remainder principally iron.

9. Agmagnetic alloy comprising "from to 8% antimony alloyed with a magnetic ma- -terial. 1 y p 1 10. A method of producing magnetic material, which consists inalloying an embrittling agent with a magnetic substance.

'11. A method of producing magnetic material, which consists in alloying a metallic 'embrittling agent with a magnetic ferrous loo alloy.

12. A method of. producing magnetic material, which consists in alloying a metallic embrittling agent with magnetic alloys of nickel and-iron.

witness whereofiI hereunto subscribe my -name this eleventh day of March A. D., 1925. K

V 'LYALL ZICKRICK'. 

